// HTMLParser Library $Name: v1_6 $ - A java-based parser for HTML
// http://sourceforge.org/projects/htmlparser
// Copyright (C) 2003 Derrick Oswald
//
// Revision Control Information
//
// $Source: /cvsroot/htmlparser/htmlparser/src/org/htmlparser/filters/HasAttributeFilter.java,v $
// $Author: derrickoswald $
// $Date: 2005/05/15 11:49:04 $
// $Revision: 1.7 $
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//

package org.htmlparser.filters;

import org.htmlparser.Attribute;
import org.htmlparser.Node;
import org.htmlparser.NodeFilter;
import org.htmlparser.Tag;

import java.util.Locale;

/**
 * This class accepts all tags that have a certain attribute, and optionally,
 * with a certain value.
 */
public class HasAttributeFilter implements NodeFilter {
    /**
     * The attribute to check for.
     */
    protected String mAttribute;

    /**
     * The value to check for.
     */
    protected String mValue;

    /**
     * Creates a new instance of HasAttributeFilter. With no attribute name,
     * this would always return <code>false</code> from {@link #accept}.
     */
    public HasAttributeFilter() {
        this("", null);
    }

    /**
     * Creates a new instance of HasAttributeFilter that accepts tags with the
     * given attribute.
     *
     * @param attribute The attribute to search for.
     */
    public HasAttributeFilter(String attribute) {
        this(attribute, null);
    }

    /**
     * Creates a new instance of HasAttributeFilter that accepts tags with the
     * given attribute and value.
     *
     * @param attribute The attribute to search for.
     * @param value     The value that must be matched, or null if any value will
     *                  match.
     */
    public HasAttributeFilter(String attribute, String value) {
        mAttribute = attribute.toUpperCase(Locale.ENGLISH);
        mValue = value;
    }

    /**
     * Get the attribute name.
     *
     * @return Returns the name of the attribute that is acceptable.
     */
    public String getAttributeName() {
        return (mAttribute);
    }

    /**
     * Set the attribute name.
     *
     * @param name The name of the attribute to accept.
     */
    public void setAttributeName(String name) {
        mAttribute = name;
    }

    /**
     * Get the attribute value.
     *
     * @return Returns the value of the attribute that is acceptable.
     */
    public String getAttributeValue() {
        return (mValue);
    }

    /**
     * Set the attribute value.
     *
     * @param value The value of the attribute to accept. If <code>null</code>,
     *              any tag with the attribute, no matter what it's value is
     *              acceptable.
     */
    public void setAttributeValue(String value) {
        mValue = value;
    }

    /**
     * Accept tags with a certain attribute.
     *
     * @param node The node to check.
     * @return <code>true</code> if the node has the attribute (and value if
     *         that is being checked too), <code>false</code> otherwise.
     */
    public boolean accept(Node node) {
        Tag tag;
        Attribute attribute;
        boolean ret;

        ret = false;
        if (node instanceof Tag) {
            tag = (Tag) node;
            attribute = tag.getAttributeEx(mAttribute);
            ret = null != attribute;
            if (ret && (null != mValue)) ret = mValue.equals(attribute.getValue());
        }

        return (ret);
    }
}
